A luminaire may be part of an illumination system which is for instance arranged within a building. At night or in the case of merely low-light ambient illumination, such a luminaire is turned on and outputs light, wherein the light output can lead by way of the presence detection apparatus to a reduced light output if no persons are present. This will lower the energy consumption, especially in cases where otherwise such a luminaire is operated at full power, for instance at night. A corresponding presence detection apparatus can be arranged within a region to be illuminated and can transmit signals to a control device, so that in the presence of a person the light output of the corresponding luminaire or corresponding luminaires is not reduced.
As a rule, such a presence detection apparatus is provided for a specific area of a building, for instance a room or the like, so that a number of luminaires are correspondingly controlled by the presence detection apparatus. As a rule, this results in only one control of a plurality of such luminaires with respect to the presence of a person, so that this plurality of luminaires is switched on, switched off or at least dimmed accordingly.
Therefore, the energy consumption can only be reduced to a certain degree.